/*
 * Copyright 2002-2022 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.hqd.ch03.v50.core.type.classreading;


import com.hqd.ch03.v50.core.NestedIOException;
import com.hqd.ch03.v50.core.asm.ClassReader;
import com.hqd.ch03.v50.core.type.AnnotationMetadata;
import com.hqd.ch03.v50.core.type.ClassMetadata;
import com.hqd.ch03.v50.io.Resource;

import java.io.IOException;
import java.io.InputStream;

/**
 * {@link MetadataReader} implementation based on an ASM
 * {@link org.springframework.asm.ClassReader}.
 *
 * @author Juergen Hoeller
 * @author Costin Leau
 * @since 2.5
 */
final class SimpleMetadataReader implements MetadataReader {

    private static final int PARSING_OPTIONS = ClassReader.SKIP_DEBUG
            | ClassReader.SKIP_CODE | ClassReader.SKIP_FRAMES;

    private final Resource resource;

    private final AnnotationMetadata annotationMetadata;


    SimpleMetadataReader(Resource resource, ClassLoader classLoader) throws IOException {
        SimpleAnnotationMetadataReadingVisitor visitor = new SimpleAnnotationMetadataReadingVisitor(classLoader);
        getClassReader(resource).accept(visitor, PARSING_OPTIONS);
        this.resource = resource;
        this.annotationMetadata = visitor.getMetadata();
    }

    @SuppressWarnings("deprecation")
    private static ClassReader getClassReader(Resource resource) throws IOException {
        try (InputStream is = resource.getInputStream()) {
            try {
                return new ClassReader(is);
            } catch (IllegalArgumentException ex) {
                throw new NestedIOException("ASM ClassReader failed to parse class file - " +
                        "probably due to a new Java class file version that isn't supported yet: " + resource, ex);
            }
        }
    }


    @Override
    public Resource getResource() {
        return this.resource;
    }

    @Override
    public ClassMetadata getClassMetadata() {
        return this.annotationMetadata;
    }

    @Override
    public AnnotationMetadata getAnnotationMetadata() {
        return this.annotationMetadata;
    }

}
